Flight Chiang Mai International Airport departs from Chiang Mai Chiang Mai International Airport at 11:15 and arrives at Singapore Changi Airport at 15:20.
The flighttime is about 3h 05m. The distance travelled ("as the bird flies"): 673 Km. So the average speed is roughly 218 Km.
There is an 1 hour time difference between Chiang Mai and Singapore